This proposal requests funds to assist in the support of the fourth biennial Gordon Research Conference on Mammary Gland Biology, to be held in New London, New Hampshire 13-17 June 1977. This highly successful series is designed to bring together, for a week of informal discussion and inquiry, biologists from a wide spectrum of subfields who share a major research interest in the mammary gland. New data and ideas to be presented in scheduled sessions will concern the origin and composition of the mammary cell membrane; the regulation and route of mammary cell uptake of dietary lipid components; phagocytic and chemical defense mechanisms in the mammary gland; aspects of control of normal and neoplastic mammary development by protein and steroid hormones; the origin, secretion, and function of lymphocytes in milk; the role of various regulatory ions and molecules in normal and pathological mammary metabolism; etiology, epidemiology, and some growth properties of human breast cancer; some biochemical and endocrinological factors regulating the initiation of copious milk production at parturition; mechanisms and control of lactose synthesis; and comparative aspects of milk chemistry. The success of this conference rests on the multidisciplinary mixture of participants, and the critical role of the speakers and discussion leaders in catalyzing active interchange of ideas, facts, methods and arguments. The scientists we have invited to assume this role are eminently capable of filling it. We need adequate funding to enable them to participate.